Brooks was still present on the field when Hodgkinson began shooting with a rifle, wounding four people including House Majority Whip Steve Scalise.
Hodgkinson is accused of shooting at several members of the Republican baseball team that was practicing this week for the annual congressional baseball game played for charity.
As for Scalise, he's still in critical condition, but he's improving. Brooks said the list was short and the other names he was told of were also GOP congressmen.
The FBI recovered the list, which was reportedly handwritten by suspect James Hodgkinson.
The list contained about a dozen names, a source said.
A spokeswoman for Capitol Police did not return CNN's request for comment. Duncan said he answered that the players were Republicans, before leaving the field. Franks added that "it's clear that (the shooting) was premeditated", but he declined to confirm the existence of a possible list, citing the ongoing investigation.
The wife of the Alexandria, Virginia, gunman said she's shocked about the attack and had no idea what her husband was planning.
She said she last saw her husband in March, when he sold off some of his belongings and moved to Virginia "to work with people to change the tax brackets", Sue Hodgkinson said. A single shot left Scalise, 51, with a shattered bone in his left hip and internal injuries that caused severe bleeding.
"Many lives would have been lost if not for the heroic actions of the two Capitol Police officers who took down the gunman despite sustaining gunshot wounds during a very, very brutal assault", Trump said.
Hodgkinson, a Belleville, Illinois, home inspector who had been living out of his van near the park, had a social media page filled with criticism of Republicans and the Trump administration.